The present invention relates to a porous shaped cellulose hydrate material with an improved scrubbing and cleaning effect, especially one in the form of a sponge cloth. Further, the invention relates to a process for the manufacture of the material and to its use as a cleaning device.
The manufacture of porous shaped cellulose hydrate materials is known. In a typical process for the preparation of this material, cellulose is first converted into viscose. Reinforcing fibers, e.g., cotton fibers of 12 to 15 mm length, or salt grains for the formation of pores, particularly crystals of Glauber's salt of appropriate grain size, may be incorporated in the viscose, if desired. The mass is then applied to an endless belt, and precipitated under the influence of heat by a coagulating agent, such as a water bath at approximately 100.degree. C. In the water bath, a major portion of the salt is dissolved and washed away. The resulting porous shaped material then passes through a precipitating bath containing aqueous sulfuric acid and, optionally, through a chlorite bleaching bath. A washing step follows next wherein the porous shaped material is thoroughly washed with water. After drying, it is cut to the desired size. Colored materials may be produced by the addition of dyes and color brighteners into the viscose mixture.
Known porous shaped cellulose hydrate materials, especially in the form of sheet-like, rectangular bodies, such as sponge cloths and floorcloths, serve for cleaning soiled surfaces by absorbing or adsorbing liquids, dust, and coarse dirt particles. There is, however, the risk that the porous material, especially a sponge cloth, may glide over the dirt and leave oily, streaky or smudgy traces instead of removing them. Moreover, the use of these cloths has the disadvantage that firmly adhering dirt, e.g., on the windows and lacquered surfaces of cars, can be removed only with considerable effort.
It has already been suggested, in German Offenlegungsschrift No. 15 03 860, to introduce a framework consisting of a porous netting of a hydrophobic organic polymer into a viscose web and then convert the viscose into a porous shaped cellulose hydrate material. The surface of this cleaning device, however, is not sufficiently rough to remove obstinate dirt. Further, the whole of its surface being covered by the netting, the cleaning effect of the porous shaped material is strongly limited, because it is no longer capable of directly contacting the surface to be cleaned.